“Not surprisingly, in an epoch before the existence of preventive methods and effective therapies, infectious diseases such as measles, diphtheria, smallpox, and pertussis topped the list of childhood killers,” according to the Health Affairs journal.

Their development started from a place of suffering. The first vaccine was against smallpox, a disease that had been around for more than 3,000 years and that killed many millions of people. In fact, it was considered “one of the world’s most feared diseases,” according to the World Health Organization.

There is evidence that people in China, Africa and Turkey used a form of smallpox inoculation, called variolation, more than 1,000 years ago, and efforts after that led to the English physician Edward Jenner noticing dairy workers were protected from the smallpox virus. He observed that they had already been infected with a less-dangerous but similar virus called cowpox; he tested his theory by scratching a small child with cowpox, and then doing so again with smallpox. The child had been immunized.

Thus, the world’s first vaccine came about in 1790, and now smallpox no longer exists in the natural world, thanks to “a lengthy and painstaking process, which identified all cases and their contacts and ensured that they were all vaccinated,” the WHO says.

The introduction of germ theory

The next major discovery came a century after Jenner’s groundbreaking work when Louis Pasteur provided evidence for the germ theory of disease, which explained that many diseases are caused by organisms too small to see with the naked eye. From there, Pasteur developed the rabies vaccine, using it on humans for the first time in 1885.

From then on, developments were made more quickly. For example, the vaccine for yellow fever, a virus spread by mosquitoes, was developed in the 1930s, and it is still recommended for anyone traveling outside the United States. At the same time, other mosquito-borne diseases still kill millions every year, so the work continues.

“The middle of the 20th century was an active time for vaccine research and development,” according to The History of Vaccines. “Methods for growing viruses in the laboratory led to rapid discoveries and innovations, including the creation of vaccines for polio. Researchers targeted other common childhood diseases such as measles, mumps, and rubella, and vaccines for these diseases reduced the disease burden greatly.”

Most people are familiar with the MMR vaccine against measles, mumps and rubella. All three vaccines became available in the 1960s and were combined in 1971, according to the Immunization Action Coalition. Another vaccine, against chickenpox, was added to the group in 2005.

The vaccine is responsible for taking the number of measles cases from 3 million to 4 million per year down to a historic low of 37 in 2004. However, the IAC points out that, in areas where people have refused to be vaccinated, the number of cases has risen in the years since then.

Vaccines today

In more recent years, a vaccine was approved in 2009 to fight the H1N1 virus (a flu strain that originated in pigs), and the HPV vaccine was developed to prevent cervical cancer, genital lesions and genital warts, and approved in 2006.

Today, diseases that can be prevented by vaccines are at or near record lows, according to the CDC, with the help of laws that require vaccination for children in schools and day cares, college students, and health care workers and patients. People immigrating to the United States are also required to get certain vaccines beforehand to help prevent the spread of dangerous diseases.

“Ironically, as vaccines have become more commonplace, they have lost some of their allure, particularly to public funding agencies,” Health Affairs says. “One might argue that vaccines have worked so well that many people now take them for granted.”

Sinclair Broadcasting is committed to the health and well-being of our viewers, which is why we’re introducing Sinclair Cares. Every month we’ll bring you information about the “Cause of the Month,” including topical information, education, awareness and prevention.